How to get the tool farther between 2 path

First tests with recently finished Burly, Rambo 1.4 with endstops
To learn how to use this machine I choose to start with drawing.
I made a pen support with switch included (something found on thingiverse and litghly moded)
So far the Z Endstop is not very accurate and the tool position can be 1 to 3mm lower.
Easily handled by the support elasticity but the pen is sometime not farther enough from the paper.
I get around the issue with the tool setting in EstClam and cheating with the home Z position.
-4mm shim under the tool while homing
-5mm engraving depth

  • 5mm per pass

I guess there’s some cleaner way to do that, I’ll be glad to get a direction to do my search
On another side I thinking of a pen holder with a more accurate and stable endswitch

I’m having difficulty understanding your question. I can visualize the issue being mechanical or because of the g-code you are using. Photos of the issue might be helpful. A link to the pen holder you are using on Thingiverse might also be helpful. The start of the g-code you are using to both home the Z axis and start cutting might be helpful. I have a hard time with a switch having a 2mm to 3mm variation in activation.

The typical way a Z “endstop” is used is a touch plate where one clip goes on the bit and the second wire is connected to a plate. The bit touching the plate stops the Z descent. I find the touch plate to be highly accurate, and I can think of a couple of ways of using a touch plate with a pen even is the pen is not electrically conductive.

When using a touch plate, you have to account for the plate thickness. My g-code for using a touch plate looks like:

G28 Z       ; Home Z
G92 Z0.5    ; Account for plate thickness
G0 Z5 F480  ; Lift the bit to remove the plate

Note that at the end of this process, my bit is at Z==5, not Z==0, so I have to be careful about the g-code I’m using in milling does not assume Z is 0.

Thanks Robert for your time,
Actually I’m a beginner and did nothing for endstops except homing the axes (LCD)
There’s a menu item in configuration about offset setting but I did not search yet the way it works. however tried it but I was not able to understand what it really do. I need to search about it.

To me the issue is mechanical, because the Z swith is not reliable enough (a screw touching a coper wire with not enough lateral stability).
At first I thought it would not be that much important in that case (experimentation) but I was wrong.

(upload:// (451.0 KB)[pen_holder_with_touch_plate_EM|attachment]

I will change the Z switch endstop system, but for now it’s not very important (i’m not milling yet) and If I just can get the tool more further (while not supposed to be in the air) to compensate this issue, I’ll be fine for now.
I guess a regular pen holder with a small rod would be easier to handle but I like the automatic way
I already have a conventionnal touch plate I’ll use with heavier tools like router or plasma cutter.

Anyway, I start with the code you give me to begin my learning.

I’m using that same pen holder, and it works very reliably with aluminum HVAC tape as contacts for the probe, but a roll of that is pretty expensive for this single purpose. I had some laying around from a recent home DIY project. Alternatively you could glue on some aluminum foil to serve as contacts.

Best of luck getting things reliable and repeatable.

Thanks Tom, I had a piec (pretty old) of that aluminium tape but I wanted something adjustable and I had not realized yet the Gcode could have done this for me (more or less pressure)

Anyway, message from Robert make me open the Gcode file, not so hard to understand the basic things.
I changed the G00 Z command to get the pencil higher while traveling (5mm, to be safe), put the depth and the home made Z switch as they should.
It works fine.

Case closed, thanks guys, I can go forward .

1 Like